This invention is primarily concerned with mechanisms which repeatedly lock a spindle in a variety of angular positions. Various locking devices have been proposed in the past. Most well known locking devices utilize either a pawl which engages a notched disk or a tapered pin which engages a precision aperture located in the face of a disk. Such arrangements have limited mechanical advantage and are adversely affected by dirt or the like contamination of engaging surfaces. While higher mechanical advantages are provided by toggle linkages or crank arrangements, these mechanisms require clearances which are not always available for a given machine design. Most of these prior art arrangements have some amount of backlash, which is objectionable when high precision alignment is required. Further, many of these arrangements provide a uni-directional locking which is capable of resisting spindle movement in only one given rotational direction.
It is therefore an object of the present invention to provide a locking mechanism having a very high mechanical advantage which provides truly zero backlash securement.
It is another object of the present invention to provide a locking mechanism of the above-described type which is capable of bi-directional locking, resisting torques which have both a clockwise and a counter-clockwise sense.
It is also an object of the present invention to provide a compact locking mechanism mounted on a shaft whose axis is arranged in non-parallel, non-intersecting arrangement with the longitudinal axis of the spindle to be locked.
A further object of the present invention is to provide a low cost locking mechanism compatible for use with conventional gears or the like indexing arrangements.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.